Question

Find the area of the polygon defined by the coordinates (0,-5),(-5,0),(-15,-20),and(-20,-15)

Answer 1

Area of the polygon defined by the given points is 62.5 sq units

Step-by-step explanation:

Step 1 :    

Let P be the point (-5,0)  Q = (0,-5), R = (-15,-20) and S = (20,-15)

We have to to find the area of the polygon PQRS

Step 2 :

The area of polygon given the vertices (x$(x_{1} ,y_{1} ), (x_{2} ,y_{2}) ... (x_{n} ,y_{n} )$ is given by

Area  = mod ( $(x_{1} y_{2} - y_{1}x_{2}) + (x_{2} y_{3} - y_{2}x_{3}) + ... (x_{n} y_{1} - y_{n}x_{1})$ ) ÷ 2

Where  $x_{n}$ is the vertex n's x coordinate , $y_{n}$ is the vertex n's y coordinate

Substituting the corresponding values ,

Area of PQRS = mod ( (25 - 0)+ (0-75) +(300-300) +( 0-75)  ) ÷ 2

                       = mod (25-75+0-75) ÷ 2

                       = mod (-125) ÷ 2 = 125 ÷ 2 = 62.5 sq units

Step 3 :    

Answer :

Area of the polygon defined by the given points is 62.5 sq units